Hi everyone, I know I've read this before somewhere on the forums but I can't remember where or find the threads.
How long is it estimated that it takes B12 treatment (injections) to replace all blood cells so that the new ones are all healthy and fit?
I'm not sure I'm asking the question exactly right, but I seem to remember something about it taking a few (or couple) months for the body to be able to create all 'healthy' red blood cells for people with pernicious anemia.
Thanks so much for your assistance!! 🙏
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Cobalt1312
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As a diabetic Cobalt1312 I understand that red blood cells have a "life" of three months hence the HbA1c blood tests I have can be taken quarterly - but don't quote me on this as I am not a medically trained person.
I have read most often that the life cycle of a red blood cell is 90 days but have read 120 and 90 to 100. This does not answer your question as it is a biological process to create healthy red blood cells. Then ya got the rest of the body has to heal.
Thanks much WIZARD6787 - very helpful info as well, and I really appreciate you insight about the life cycle of a red blood cell not being the same as how long it takes the body to make new ones - that's a really good distinction!
Casasue just to make sure, I think you're saying it takes 72 hours after injecting for B12 to help the new blood cells that are being made at that time?
Casasue not sure what it is that you are referring to as 72 hours - an injection gets into the blood stream immediately - or near enough on a human timescale to make no difference.
@Cobalt1312, the body only creates new red blood cells to replace cells that have died or have been lost. so, after giving blood it will create new red blood cells quite quickly - think it is usually reckoned to take a month. However, outside of this the production of new red blood cells depends on old ones 'dying'. Red blood cells 'live' for about 120 days on average so to completely replace macrocytic blood cells would probably take 4 months.
Please note, however, that symptoms of B12 deficiency are not necessarily due to the anaemia it causes.
This is the way I look at it. If one injects on day one then on day 120 it is assumed all red blood cells that existed on day one have been lost or replaced with the benefit of having B12 injections. It does not follow that all the red blood cells formed within the 120 days are healthy due to having the benefit of B12 injections. Nor is it known that the red blood cells that were formed without the benefit of B12 injection live the average life span as a healthy red blood cell. Pretty much it is going to take a while.
If we inject into a muscle or subcutaneously the B12 doesn't go straight into the blood stream at all. We would need to inject it directly into a blood vessel for that to happen. Further any B12 sold as a "depot" is taken up slowly - depot meaning a deposit or store. I assume the fastest would be two days given the EOD advice yet it may well be much slower.
Only a lifetime working in biosciences. Hydroxy - is a B12 thats taken up more slowly than other forms. Depot injections are also used to slowly deliver antipsychotics and contraceptive medication .
I don’t see the word Depot, and I don’t see anything that says other forms of B12 are absorbed faster.
But I do see “All forms of B12—CNCbl, MeCbl, OHCbl, and AdCbl—seem to be absorbed with similar efficiency in the blood stream but differ in overall bioavailability, as reflected by their tissue retention rates.”
Note “absorbed with similar efficiency”.
And I also see “For the majority of the population, all B12 forms may likely have similar bioavailabilities and physiological effects”.
I read, elsewhere, that hydroxy is longer lasting in the body than methyl, which is why it is the preferred variant for the NHS in the UK.
But I haven’t read that hydroxy is slower to be absorbed, just slower to be excreted.
Though perhaps you have read this elsewhere? But I really can’t see it in the article I quoted, though perhaps you could point me to the exact words that you found in it that supported your view?
I remain anxious to build the most accurate picture I can, for a lay person, of how B12 operates.
I understand it is slow release When injected into a muscle, it creates a store or 'depot' of medication which is released slowly into the body over several weeks.
Interested to know how to get a quicker result if we've forgotten our B12 injections for a week? If I inject today, it won't make an instant improvement, maybe I'll see an improvement in a few days? Thank you. P.s. I should really keep a diary!
Firstly, I don’t doubt the ‘depot’ effect of hydroxy; I just doubt that the other forms don’t work exactly the same way.
Secondly, what form are you using? If there is something in what Bellabab says, then one of the forms other than hydroxy should act quicker.
But our (purely anecdotal) experience is that hydroxy kicks in straight away, a Thursday evening jab setting up in good time for a busy weekend starting the next day a.m.
The textbook answer is that red cells have a lifespan of 110-120 days. Once you are receiving B12 and everything else is there to make new cells, then we see a reticulocyte response within 3 days. [In iron replacement it takes longer; up to about 10 days] and then it's just a matter of keeping the furnace stoked. In four months time, all the old cells will have been recycled.
In actual fact, it's likely to be a bit sooner than that, but it depends on other things like 'were you anaemic at the outset?' If so, the response will be a bit more vigorous. Megaloblastic erythropoiesis, as seen in B12 and/or folate deficiency, is one of a class of conditions known as 'Ineffective Erythropoiesis' which is why some patients have a mild jaundice too. But to cut a long ramble short, Start on B12, then blood is completely back to normal in 115 days.
Blood might be normal in ‘X’ time but damage to nerves can take a while to repair (hopefully if not permanent) and B12 replacement needs to continue to prevent it happening again.
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